Zoom Optical System

ABSTRACT

A zoom optical system and automated luminaire are provided. The zoom optical system includes a light source and compensator, variator, and objective lens groups. The light source illuminates an object in an object plane. The compensator lens group is optically coupled to the object without intervening lenses, has a positive optical power, six lenses, and moves relative to the object plane. The variator lens group is optically coupled to the compensator lens group without intervening lenses, has a negative optical power, three lenses, and moves relative to the object plane and the compensator group. The objective lens group is optically coupled to the variator lens group without intervening lenses, has a second positive optical power, three lenses, remains in a fixed position relative to the object plane, and projects an image of the object without intervening lenses between the objective lens group and the projected image.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/059,666, filed Aug. 9, 2018 by Jan Vilem, et al. entitled, “ZoomOptical System”, which claims priority to U.S. Provisional ApplicationNo. 62/553,324, filed Sep. 1, 2017 by Jan Vilem, et al. entitled, “ZoomOptical System”, both of which are incorporated by reference herein asif reproduced in their entirety.

TECHNICAL FIELD OF THE DISCLOSURE

The disclosure generally relates to an automated luminaire, specificallyto a zoom optical system for use in an automated luminaire.

BACKGROUND

Luminaires with automated and remotely controllable functionality arewell known in the entertainment and architectural lighting markets. Suchproducts are commonly used in theatres, television studios, concerts,theme parks, night clubs and other venues. Such a luminaire may providecontrol over the direction the luminaire is pointing and thus theposition of the light beam on the stage or in the studio. Thisdirectional control may be provided via control of the luminaire'sorientation in two orthogonal axes of rotation usually referred to aspan and tilt. Some products provide control over other parameters suchas the intensity, color, focus, beam size, beam shape and beam pattern.

SUMMARY

In a first embodiment, a zoom optical system includes a light source, acompensator lens group, a variator lens group, and an objective lensgroup. The light source is configured to illuminate an object located inan object plane. The compensator lens group is optically coupled to theobject without intervening lenses, has a first positive optical power,includes six lenses, and is configured to move relative to the objectplane. The variator lens group is optically coupled to the compensatorlens group without intervening lenses, has a negative optical power,includes three lenses, and is configured to move relative to the objectplane and the compensator group. The objective lens group is opticallycoupled to the variator lens group without intervening lenses, has asecond positive optical power, includes three lenses, and is configuredto remain in a fixed position relative to the object plane and toproject an image of the object without intervening lenses between theobjective lens group and the image of the object.

In a second embodiment, an automated luminaire includes a light source,a zoom optical system, and a controller. The light source is configuredto emit a first light beam and illuminate an object located in an objectplane. The zoom optical system is optically coupled to the objectwithout intervening lenses and includes a compensator lens group, avariator lens group, and an objective lens group. The compensator lensgroup has a first positive optical power, includes six lenses, and isconfigured to receive the first light beam as modified by the objectwithout intervening lenses and to emit a second light beam. The variatorlens group has a negative optical power, includes three lenses, and isconfigured to receive the second light beam without intervening lensesand to emit a third light beam. The objective lens group has a secondpositive optical power, includes three lenses, and is configured toremain in a fixed position relative to the object plane. The objectivelens group is further configured to receive the third light beam withoutintervening lenses, and to project an image of the object withoutintervening lenses between the objective lens group and the image of theobject. The controller is configured to move the compensator lens groupand the variator lens group independently along an optical axis of thezoom optical system.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in conjunction with theaccompanying drawings in which like reference numerals indicate likefeatures.

FIG. 1 presents a block diagram of a system including automatedluminaires according to the disclosure;

FIG. 2 presents a side view of the elements of a zoom optical systemaccording to the disclosure;

FIG. 3 presents an isometric view of the zoom optical system of FIG. 2in a first configuration;

FIG. 4 presents an isometric view of the zoom optical system of FIG. 2in a second configuration;

FIG. 5 presents a schematic block diagram of a moving head of anautomated luminaire according to the disclosure; and

FIG. 6 presents a block diagram of a control system according to thedisclosure.

DETAILED DESCRIPTION

Preferred embodiments are illustrated in the figures, like numeralsbeing used to refer to like and corresponding parts of the variousdrawings.

Disclosed herein is an automated luminaire that includes a light source,a controller, and a zoom optical system comprising three lens groups: amoveable, positive power compensator lens group, closest to the lightsource, a moveable, negative power variator lens group in the middle,and a fixed, positive power objective group, farthest from the lightsource.

FIG. 1 presents a block diagram of a system 100 including automatedluminaires according to the disclosure. Lighting system 100 includes aplurality of multiparameter automated luminaires 112 according to thedisclosure. Each luminaire 112 includes a light source, light modulationdevices, electric motors coupled to mechanical drive systems, andcontrol electronics. In addition to being connected to a power sourceeither directly or through a power distribution system, each luminaire112 is connected in series or in parallel via data link 114 to one ormore control desks (or consoles) 115. The lighting system 100 isconfigured to be controlled by an operator using the control desk 115.While data link 114 is depicted as a wired communication link, it willbe understood that in other embodiments the data link 114 may be awireless communication link.

Control of an individual automated luminaire 112 is typicallyeffectuated by electromechanical devices within the luminaire 112 andelectronic circuitry including firmware and software within the controldesk 115 and/or the luminaire 112. The luminaire 112 and its includedelectronic circuitry may also be referred to collectively as a fixture.In many of the figures herein, elements such as electromechanicalcomponents (including motors and electronic circuitry including softwareand firmware and some hardware) are not shown in order to simplify thedrawings. Persons of skill in the art will recognize where these partshave been omitted.

FIG. 2 presents a side view of the elements of a zoom optical system 200according to the disclosure, as used in one or more of the luminaires112 in system 100. The zoom optical system 200 includes a light source202 and three groups of lenses: the compensator group, the variatorgroup, and the objective group. The objective group includes lenses 210,212, and 214. The variator group includes lenses 220. 222 and 224. Thecompensator group includes lenses 230, 232, 234, 236, 238, and 239. Thelight source 202 and the compensator, variator, and objective lensgroups are coaxially located on an optical axis 204 of the zoom opticalsystem 200.

The compensator group lenses form a converging (or positive power)group, the variator group lenses form a diverging (or negative power)group, and the objective group lenses form a converging group. Thecompensator group has a focal length of 191.89 millimeters (mm), thevariator group has a focal length of −39.534 mm, and the objective grouphas a focal length of 39.794 mm. For the purposes of this disclosure,group focal lengths within 10% of the disclosed lengths are consideredsubstantially equal to the disclosed focal lengths.

As will be explained in more detail with reference to FIGS. 3 and 4, thecompensator and variator groups are configured to move independentlyalong the optical axis 204 relative to the light source 202, theobjective group, and each other. The moving lens groups may bemechanically coupled to hand-operated manual controls or may be coupledto motors, linear actuators, or other electromechanically controlledmechanisms for motion. Such electromechanical mechanisms may be underthe control of a microcontroller or other programmable processing systemincluded in the light fixture. In some embodiments, the processingsystem may be controlled locally via a user interface included in thelight fixture. In other embodiments, the processing system may be inwired or wireless communication with a remotely located control consolethat an operator uses to indicate a desired configuration for the zoomoptical system.

The zoom optical system 200 includes an object plane 240. One or moreobjects to be imaged by the zoom optical system 200 are located in oradjacent to the object plane 240. Examples of objects to be imagedinclude a static or rotating gobo mounted on a gobo wheel or other gobocarrier, and a variable iris, an aperture wheel, or other mechanism forproducing a light beam of a selected size. Where more than one suchobject to be imaged is included in the zoom optical system 200, it willbe understood that the objects may be located in individual planesadjacent to the object plane 240. As shown in FIG. 2, the right end ofthe zoom optical system 200 may be referred to as the object end and theleft end as the image end.

As may be seen in FIG. 2, the compensator lens group is opticallycoupled to the one or more objects in the object plane 240 withoutintervening lenses, the variator lens group is coupled to thecompensator lens group without intervening lenses, the objective lensgroup is coupled to the variator lens group without intervening lenses,and the objective lens group projects an image of the one or moreobjects in the object plane 240 without further intervening lenses.

The lenses of this embodiment are described in Table 1, identified bytheir reference characters from FIG. 2. The column ‘Descr.’ presents adescription of the shape of each lens, where “D” is a diameter of thelens, “RI” is a radius of curvature of the lens on its image side, and“RO” is a radius of curvature of the lens on its object side. Alldiameter and radius of curvature measurements are in mm. For thepurposes of this disclosure, radii of curvature within 10% of thedisclosed radii are considered substantially equal to the disclosedradii of curvature.

TABLE 1 Schott CDGM Ref. Glass Glass Char. Descr. Type Type Power 210 D150, RI 152.5, RO 1000.0 N-BK7 H-K9L Pos 212 D136, RI 138.1, RO 401.3N-BK7 H-K9L Pos 214 D136, RI −401.3, RO −401.3 N-SF6 H-ZF7LA Neg 220 D54, RI 166.0, RO −34.5 N-SK16 H-ZK9A Neg 222 D47, RI −47.8, RO −58.1N-SK16 H-ZK9A Neg 224 D47, RI 58.1, RO −5370.8 N-SF6 H-ZF7LA Pos 230D44, RI 53.6, RO 119.3 N-BK7 H-K9L Pos 232 D44, RI −36.0, RO 57.8 N-SF6H-ZF7LA Neg 234 D44, RI −297.1, RO 44.8 N-BK7 H-K9L Pos 236 D44, RI57.1, RO 67.6 N-BK7 H-K9L Pos 238 D44, RI −52.0, RO 249.9 N-SF6 H-ZF7LANeg 239 D44, RI 51.0, RO 530.8 N-BK7 H-K9L Pos

All lenses are spherical lenses. The columns “Schott Glass Type’ and‘CDGM Glass Type’ identify types of glass material for each lens,specified in a type designator notations used by their respectivemanufacturers. Schott glass is manufactured by Schott AG of Mainz,Germany. CDGM glass is manufactured by CDGM Glass Company Ltd. ofChengdu, China. Glass type values that include the letter “F” identify alens made of flint glass. Glass type values that include the letter “K”identify a glass made of crown glass. “ZF” and “SF” indicate ‘DenseFlint,’ “ZK” and “SK” indicate ‘Dense Crown,’ and “BK” indicates‘Borosilicate Crown.’ One or more of the lenses includes anantireflective coating applied to one or both surfaces of the lens. Thecolumn “Power” indicates whether the lens is a positive power (“Pos”)lens or a negative power (“Neg”) lens.

Table 2 describes spacing between lens pairs at center points of theiradjacent surfaces. Because the pairs 212-214 and 222-224 are in contactwith each other, they may be referred to as doublets. The spacingbetween lens pairs within the compensator, variator, and objectivegroups remains constant. The overall lengths of the objective, variator,and compensator groups are 60.9 mm, 26.5 mm, and 57.1 mm, respectively.These lengths do not change as the compensator and variator groups moverelative to one another and the objective group along the optical axis204.

TABLE 2 Spacing Between Lens Pair Lenses (mm) 210-212 0.3 212-214contact 220-222 13.288 222-224 contact 230-232 3.131 232-234 11.1234-236 1.6 236-238 0.98 238-239 0.3

The compensator, variator, and objective lens groups of the zoom opticalsystem 200 have six, three, and three lenses, respectively. It will berecognized by a person of skill in the art that, in other embodiments,positive/negative/positive compensator/variator/objective lens groupsmay comprise lens groups of more or fewer than six/three/three lenseseach, including lens ‘groups’ with only a single lens.

A first light beam emitted by the light source 202 converges andilluminates an object to be imaged, located in the object plane 240, andthen diverges as it approaches the compensator group. The compensatorgroup receives the first light beam, as modified by any object placed inthe first beam in the object plane 240, and emits a second light beam.The variator group receives the second light beam and emits a thirdlight beam. The objective group receives the third light beam and emitsa fourth light beam, which is the light beam emitted by the zoom opticalsystem 200. The objective group remains in a fixed location relative tothe light source 202, while both the variator and compensator groupsmove independently along the optical axis 204. As such, each of thecompensator, variator, and objective lens groups may be said to beoptically coupled to its preceding optical element in the zoom opticalsystem 200.

Movement of the variator group primarily controls the overall focallength (light output angle or beam angle) of the emitted light beam.Movement of the compensator group primarily controls whether an objectin the object plane 240 or in a plane adjacent to the object plane 240is in focus. In combination, the positions of the compensator andvariator groups determine a beam angle (zoom) of the emitted beam and adistance from the objective group at which a projected image of theobject plane is focused. As such, the compensator, variator, andobjective groups may also be referred to respectively as focus group,zoom group, and fixed group.

FIG. 3 presents an isometric view of the zoom optical system 200 of FIG.2 in a first configuration. In the first configuration, the zoom opticalsystem emits a light beam with a maximum beam angle. FIG. 4 presents anisometric view of the zoom optical system 200 of FIG. 2 in a secondconfiguration. In the second configuration, both the compensator groupand the variator group have moved back toward the light source 202 andthe zoom optical system 200 emits a light beam with a minimum beamangle. The zoom ratio between the beam emitted in the secondconfiguration and the beam emitted in the first configuration is 14:1.

Table 3 presents inter-group measurements in the first and secondconfigurations. All measurements are in millimeters.

TABLE 3 First Config. Second Config. Front of light source to image 336336 side of objective group Front of light source to object 103.3 69.3side of compensator group Object side of compensator group 137.5 62.5 toobject side of variator group Object side of variator group to 34.2143.2 object side of objective group

FIG. 5 presents a schematic block diagram of a moving head 500 of anautomated luminaire according to the disclosure, as used in one or moreof the luminaires 112 in system 100. It will be understood that themoving head of a luminaire 112 would include other optical elements andmechanical system that are omitted from the moving head 500 for clarityof explanation.

The moving head 500 includes a zoom optical system 550 that is similarto the zoom optical system 200 and includes additional elements. Thelenses of the objective group are fixedly coupled to the moving head500. The lenses of the variator group are mechanically coupled to themoving head 500 via a drive mechanism 506 that is actuated by a motor504. The lenses of the compensator group are mechanically coupled to themoving head 500 via a drive mechanism 510 that is actuated by a motor508. The drive mechanisms 506 and 510 produce linear motion of thevariator and compensator groups, respectively, along an optical axis 504of the zoom optical system 550. The drive mechanism 506 and motor 504and the drive mechanism 510 and motor 508 are lead screw mechanismsactuated by rotary motors, but it will be understood that in otherembodiments cams, gears, sliders, linear actuators, linkages, or othersuitable mechanisms may be used to provide linear motion of thecompensator and/or variator groups.

A controller 502 (typically located in a static upper enclosure of theautomated luminaire) controls the motor 504 via a control link 554, andcontrols the motor 508 via a control link 552. The control links 552 and554 may be wires or optical signal conductors. The controller 502 isconfigured to receive control signals via a data link 114 (as describedwith reference to FIG. 1) and, in response to the received controlsignals, operate one or both of the motors 504 and 508 to move thevariator and compensator groups, respectively, to desired positionsrelative to the object plane 540.

In a one embodiment, the controller 502 operates the motor 504 inresponse to a control signal on a first control channel of the data link114 and operates the motor 508 in response to a control signal on asecond control channel of the data link 114. The controller 502 isfurther configured to prevent the variator and compensator groups fromcolliding with each other when operating one or both of the motors 504and 508.

The data link 114 uses DMX512 (Digital Multiplex) protocol, which is anindustry standard, unidirectional communication protocol. In otherembodiments, other communication protocols may be used, includingArt-Net, ACN (Architecture for Control Networks), and Streaming ACN.

FIG. 6 presents a block diagram of a control system 600 according to thedisclosure. The control system 600 is suitable for use as the controller502 described with reference to FIG. 5, as well as a controller in theautomated luminaires 112 described with reference to FIG. 1. The controlsystem 600 includes a processor 602 electrically coupled to a memory604. The processor 602 is implemented by hardware and software. Theprocessor 602 may be implemented as one or more Central Processing Unit(CPU) chips, cores (e.g., as a multi-core processor), field-programmablegate arrays (FPGAs), application specific integrated circuits (ASICs),and digital signal processors (DSPs).

The processor 602 is further electrically coupled to and incommunication with a communication interface 606. The processor 602 isalso coupled via control interface 608 to control links 552 and 554 and,in other embodiments, to one or more other sensors, motors, actuators,controls and/or other devices. The communication interface 606 iscoupled to, and configured to communicate via, the data link 114.

The control system 600 is suitable for implementing processes, zoomoptical system control, and other functionality as disclosed herein,which may be implemented as instructions stored in the memory 604 andexecuted by the processor 602. The memory 604 comprises one or moredisks, tape drives, and/or solid-state drives and may be used as anover-flow data storage device, to store programs when such programs areselected for execution, and to store instructions and data that are readduring program execution. The memory 604 may be volatile and/ornon-volatile and may be read-only memory (ROM), random access memory(RAM), ternary content-addressable memory (TCAM), and/or staticrandom-access memory (SRAM).

While the disclosure has been described with respect to a limited numberof embodiments, those skilled in the art, having benefit of thisdisclosure, will appreciate that other embodiments may be devised whichdo not depart from the scope of the disclosure herein. While thedisclosure has been described in detail, it should be understood thatvarious changes, substitutions and alterations can be made heretowithout departing from the spirit and scope of the disclosure.

What is claimed is:
 1. A zoom optical system comprising: a light sourceconfigured to illuminate an object located in an object plane; acompensator lens group, optically coupled to the object withoutintervening lenses, having a first positive optical power, comprisingsix lenses, and configured to move relative to the object plane; avariator lens group, optically coupled to the compensator lens groupwithout intervening lenses, having a negative optical power, comprisingthree lenses, and configured to move relative to the object plane andthe compensator lens group; and an objective lens group, opticallycoupled to the variator lens group without intervening lenses, having asecond positive optical power, comprising three lenses, and configuredto remain in a fixed position relative to the object plane and toproject an image of the object without intervening lenses between theobjective lens group and the image of the object.
 2. The zoom opticalsystem of claim 1, wherein focal lengths of the compensator lens group,variator lens group, and objective lens group are substantially equal to191.89, −39.534, and 39.794, respectively.
 3. The zoom optical system ofclaim 1, wherein the compensator lens group and variator group arefurther configured to be moved by an operator of the zoom optical systemto selected positions relative to the object plane.
 4. The zoom opticalsystem of claim 1, wherein the compensator lens group and variator groupare configured to be moved by a remotely located operator of the zoomoptical system to selected positions relative to the object plane. 5.The zoom optical system of claim 1, wherein the variator lens groupcomprises a first doublet and the objective lens group comprises asecond doublet.
 6. The zoom optical system of claim 1, wherein: the sixlenses of the compensator lens group, listed in sequence beginning witha lens closest to the object plane, comprise positive, negative,positive, positive, negative, and positive power lenses; the threelenses of the variator lens group, listed in sequence beginning with alens closest to the object plane, comprise positive, negative, andnegative power lenses; and the three lenses of the objective lens group,listed in sequence beginning with a lens closest to the object plane,comprise negative, positive, and positive power lenses.
 7. The zoomoptical system of claim 1, wherein: the six lenses of the compensatorlens group, listed in sequence beginning with a lens closest to theobject plane, comprise glass of types H-K9L, H-ZF7LA, H-K9L, H-K9L,H-ZF7LA, and H-K9L; the three lenses of the variator lens group, listedin sequence beginning with a lens closest to the object plane, compriseglass of types H-ZF7LA, H-ZK9A, and H-ZK9A; and the three lenses of theobjective lens group, listed in sequence beginning with a lens closestto the object plane, comprise glass of types H-ZF7LA, H-K9L, and H-K9L.8. The zoom optical system of claim 1, wherein: the six lenses of thecompensator lens group, listed in sequence beginning with a lens closestto the object plane, have radii of curvature substantially equal to: RIRO 51.0 530.8 −52.0 249.9 57.1 67.6 −297.1 44.8 −36.0 57.8 53.6 119.3;

the three lenses of the variator lens group, listed in sequencebeginning with a lens closest to the object plane, have radii ofcurvature substantially equal to: RI RO 58.1 −5370.8 −47.8 −58.1 166.0−34.5;

and the three lenses of the objective lens group, listed in sequencebeginning with a lens closest to the object plane, have radii ofcurvature substantially equal to: RI RO −401.3 −401.3 138.1 401.3 152.51000.0,

where RI is the radius of curvature of an image side of the lens, RO isthe radius of curvature of an object side of the lens, and all radii arein millimeters.
 9. An automated luminaire, comprising: a light sourceconfigured to emit a first light beam and illuminate an object locatedin an object plane; a zoom optical system optically coupled to theobject without intervening lenses, the zoom optical system comprising: acompensator lens group having a first positive optical power, comprisingsix lenses, and configured to receive the first light beam as modifiedby the object without intervening lenses and to emit a second lightbeam; a variator lens group having a negative optical power, comprisingthree lenses, and configured to receive the second light beam withoutintervening lenses and to emit a third light beam; and an objective lensgroup having a second positive optical power, comprising three lenses,and configured to remain in a fixed position relative to the objectplane, to receive the third light beam without intervening lenses, andto project an image of the object without intervening lenses between theobjective lens group and the image of the object; and a controllercoupled to the compensator lens group and the variator lens group andconfigured to move the compensator lens group and the variator lensgroup independently along an optical axis of the zoom optical system.10. The automated luminaire of claim 9, wherein: the controllercomprises: a first drive mechanism mechanically coupled to thecompensator lens group; and a second drive mechanism mechanicallycoupled to the variator lens group; and the controller is configured toactuate one or both of the first and second drive mechanisms to move thecompensator lens group and/or the variator lens group to a desiredposition relative to the object plane.
 11. The automated luminaire ofclaim 10, wherein one or both of the first and second drive mechanismsis a lead screw mechanism actuated by a rotary motor.
 12. The automatedluminaire of claim 10, wherein the controller comprises a communicationinterface and is configured to operate one or both of the first andsecond drive mechanisms in response to a control signal received via thecommunication interface.
 13. The automated luminaire of claim 12,wherein the controller operates the first drive mechanism in response toa first control signal received on a first control channel and operatesthe second drive mechanism in response to a second control signalreceived on a second control channel.
 14. The automated luminaire ofclaim 12, wherein the controller is configured to prevent the variatorlens group and the compensator lens group from colliding with each otherwhen operating one or both of the first and second drive mechanisms. 15.The automated luminaire of claim 12, wherein the communication interfacecomprises a DMX512 (Digital Multiplex) protocol.
 16. The automatedluminaire of claim 9, wherein the variator lens group comprises a firstdoublet and the objective lens group comprises a second doublet.
 17. Theautomated luminaire of claim 9, wherein: the six lenses of thecompensator lens group, listed in sequence beginning with a lens closestto the object plane, comprise positive, negative, positive, positive,negative, and positive power lenses; the three lenses of the variatorlens group, listed in sequence beginning with a lens closest to theobject plane, comprise positive, negative, and negative power lenses;and the three lenses of the objective lens group, listed in sequencebeginning with a lens closest to the object plane, comprise negative,positive, and positive power lenses.
 18. The automated luminaire ofclaim 9, wherein: the six lenses of the compensator lens group, listedin sequence beginning with a lens closest to the object plane, comprisecrown glass, flint glass, crown glass, crown glass, flint glass, andcrown glass; the three lenses of the variator lens group, listed insequence beginning with a lens closest to the object plane, compriseflint glass, crown glass, and crown glass; and the three lenses of theobjective lens group, listed in sequence beginning with a lens closestto the object plane, comprise flint glass, crown glass, and crown glass.